NdisMFreePort function (ndis.h)

Article
04/18/2022

The NdisMFreePort function frees an NDIS port that was previously allocated with the NdisMAllocatePort function.

Syntax

NDIS_STATUS NdisMFreePort(
       NDIS_HANDLE      NdisMiniportHandle,
  [in] NDIS_PORT_NUMBER PortNumber
);

Parameters

NdisMiniportHandle

The miniport adapter handle that NDIS passed to the MiniportAdapterHandle parameter of the MiniportInitializeEx function.

[in] PortNumber

The number of the NDIS port that NDIS should free. The PortNumber value is an NDIS_PORT_NUMBER value, which has a ULONG data type. NDIS provided the port number in the PortNumber member of the NDIS_PORT_CHARACTERISTICS structure when the miniport driver called the NdisMAllocatePort function.

The port number can be a number from 1 through 0xffffff. You cannot set PortNumber to zero, which indicates the default port.

Return value

NdisMFreePort can return one of the following values:

Return code	Description
NDIS_STATUS_SUCCESS	NDIS successfully freed the resources for the port.
NDIS_STATUS_INVALID_PORT	NDIS could not free the resources for the port because the port number was invalid.
NDIS_STATUS_INVALID_PORT_STATE	NDIS could not free the resources for the port because the port was is in a state where the free operation is invalid. To free the port, the port must be in the allocated state.
NDIS_STATUS_INVALID_DATA	The port number that was supplied at the PortNumber parameter was invalid.

Remarks

If a miniport driver allocated a port by calling the NdisMAllocatePort function, the driver must free the port before it returns from its MiniportHaltEx function. If the miniport driver activated the port by issuing a NetEventPortActivation Plug and Play (PnP) event, the driver must issue a NetEventPortDeactivation PnP event for the port before freeing the port.

When a miniport driver calls NdisMFreePort to free a port, NDIS also frees the port number that is assigned to the freed port so that NDIS can reuse the port number.

The miniport driver must not attempt to free the default port.

Requirements

Requirement	Value
Minimum supported client	Supported in NDIS 6.0 and later.
Target Platform	Universal
Header	ndis.h (include Ndis.h)
Library	Ndis.lib
IRQL	<= DISPATCH_LEVEL
DDI compliance rules	Irql_Miniport_Driver_Function(ndis)